PSR Standards

🎯 Key Points

• ✓PSR-1: Basic Coding Standard - Fundamentale kodestandarder for PHP filer
• ✓PSR-12: Extended Coding Style - Detaljeret style guide for PHP kode formatering
• ✓PSR-4: Autoloading - Standard for autoloading classes baseret på namespace
• ✓PSR-7: HTTP Message Interfaces - Interfaces for HTTP requests og responses
• ✓PSR-11: Container Interface - Common interface for dependency injection containers
• ✓PSR-15: HTTP Server Request Handlers - Middleware og request handler interfaces
• ✓PSR-18: HTTP Client - Standard interface for HTTP client libraries
• ✓PSR-3: Logger Interface - Common logging interface (Psr\Log\LoggerInterface)
• ✓PSR-6: Caching Interface - Standard for cache libraries
• ✓PSR-16: Simple Cache - Simplified caching interface for common use cases

💻 Kode Eksempel

<?php

// PSR-4 Autoloading example
// composer.json configuration:
// "autoload": {
//   "psr-4": {
//     "Acme\\Blog\\": "src/"
//   }
// }

// PSR-3 Logger Interface Implementation
namespace Acme\Blog\Services;

use Psr\Log\LoggerInterface;
use Psr\Log\LogLevel;

class FileLogger implements LoggerInterface {
    private string $logFile;
    
    public function __construct(string $logFile) {
        $this->logFile = $logFile;
    }
    
    public function log($level, $message, array $context = []): void {
        $timestamp = date('Y-m-d H:i:s');
        $contextStr = !empty($context) ? json_encode($context) : '';
        $logMessage = "[{$timestamp}] {$level}: {$message} {$contextStr}" . PHP_EOL;
        file_put_contents($this->logFile, $logMessage, FILE_APPEND);
    }
    
    public function emergency($message, array $context = []): void {
        $this->log(LogLevel::EMERGENCY, $message, $context);
    }
    
    public function alert($message, array $context = []): void {
        $this->log(LogLevel::ALERT, $message, $context);
    }
    
    public function critical($message, array $context = []): void {
        $this->log(LogLevel::CRITICAL, $message, $context);
    }
    
    public function error($message, array $context = []): void {
        $this->log(LogLevel::ERROR, $message, $context);
    }
    
    public function warning($message, array $context = []): void {
        $this->log(LogLevel::WARNING, $message, $context);
    }
    
    public function notice($message, array $context = []): void {
        $this->log(LogLevel::NOTICE, $message, $context);
    }
    
    public function info($message, array $context = []): void {
        $this->log(LogLevel::INFO, $message, $context);
    }
    
    public function debug($message, array $context = []): void {
        $this->log(LogLevel::DEBUG, $message, $context);
    }
}

// PSR-12 Compliant code style
class UserController {
    public function __construct(
        private LoggerInterface $logger,
        private UserRepository $repository
    ) {}
    
    public function store(array $data): User {
        $this->logger->info('Creating new user', ['email' => $data['email']]);
        return $this->repository->create($data);
    }
}

⭐ Best Practices

• ✓Følg PSR-12 for code style - brug automated tools som PHP-CS-Fixer til at enforce standards
• ✓Implementer PSR-4 autoloading i alle projekter - det er industristandarden
• ✓Brug PSR interfaces i type hints frem for konkrete implementationer for bedre testbarhed
• ✓Konfigurer din IDE til at følge PSR-12 formatting automatisk
• ✓For libraries og packages, følg PSR standarder religiøst for maksimal kompatibilitet
• ✓Brug Composer's autoload standarder som følger PSR-4 out of the box
• ✓Document hvilke PSR standarder dit projekt følger i README filen
• ✓Run static analysis tools (PHPStan, Psalm) der checker PSR compliance